Tampilkan postingan dengan label self-toning. Tampilkan semua postingan
Tampilkan postingan dengan label self-toning. Tampilkan semua postingan

Kamis, 05 Juni 2008

Practicus In The Studio: Printing Processes For Portraiture.

           I find that nowadays people are rather apt to get into a groove over their printing methods and apparently forget that any other process exists except that which they happen to be working. It thus occurs to me that a brief review of the Different printing media at present available, with notes on the characteristics of each, would be of service to those who wish to vary their work.
           The uncertain character of daylight in Great Britain has made bromide and gaslight papers very popular, and an overwhelming proportion of portrait work is now produced upon them, but thanks to the almost universal supply of electric current, we are not now altogether dependent upon daylight for what may be generally classed as "printing out" as distinguished from developing processes.
           The quality of the negative is an important factor in the production of the print, and only a small proportion of current negatives would yield even a passable result upon the old albumenized paper which for many years was almost exclusively used, so much so, in fact, that a print was hardly regarded as a "real" photograph unless it was made upon it By reason of the quality of the negative required, and because it was impossible to produce it by modern factory methods albumenized paper is now only a memory, and it is impossible to procure even a small quantity through the ordinary channels. Hence it is unnecessary to touch upon it otherwise than by way of reminiscence. Bromide paper in its various grades has taken its place, and I therefore put it first upon the list as being the process for the million, or that proportion of it who practise photography.
           Although in such general use, few portraitists fully appreciate the wonderful variety of surfaces, speeds, and character of emulsions which are available. I cannot fairly allude to any specific makes by name, but will be content to refer my readers to the advertisements in the B.J. Almanac, and the advertisement pages of the weekly Press. Bromide papers may roughly be divided into several groups, although these somewhat overlap each other. We may divide them by speed, that is to say, the time necessary to produce a print from a given negative by a given illumination; by the degree of contrast which can be obtained from the same negative by the surface texture, and by the colour of the paper base itself apart from the image. Thus we have "slow" and "rapid" papers, hard or contrasty, and soft, rough, smooth "platino matt," "satin," and glossy, these giving a range from rough drawing paper to a surface like glass. In many cases certain grades come into two or more of these classes. Thus we may have rough rapid, smooth rapid, hard cream and soft cream, and the same in white. In this great variety lies one of the principal advantages of bromide paper, for there is hardly a negative which is capable of being printed at all for which a paper which will give the best result cannot be found. Many printers use only one variety of paper, and trust to their skill in exposure and development to produce even results from all classes of negatives, but from experience I can assert that a very ordinary worker can produce a better result upon "hard" paper from a flat negative than an expert can upon the average kind. Therefore I advise every printer to have by him a small stock of special papers, so that he can at once select the quality necessary for exceptional densities of image. While not recommending this course to he carried too far and to encumber one self with too many kinds, I would point out the influence of colour and surface in certain cases. Suppose that we have a hard, chalky negative; we can use for this a "cream crayon soft" paper. This not only reduces the contrast of the image but tones down the glare of the whites, while the slightly rough texture gives further aid me direction. With a very soft negative we may choose a satin surface paper, that is, one with a semi-gloss, which gives a richness to the shadows. A full gloss paper would be even better, but for high-class -work a glossy surface is rarely acceptable. Further modification may be obtained by toning the image to a sepia colour, a course generally advisable with harsh contrasts, as brown and white usually gives a softer result than black and white when both print are of the tame quality. I strongly the practice of toning bromides irrespective of quality; every day thousands of prints which are of fatrly good quality in black and white are spoiled by being converted into poor, flat, rusty sepias. If I have the slightest doubt as to the resulting tone of a print I would- leave it in black and white, and if the order were for sepia prints I would ask permission to submit a black and white print when sending the proofs.
           Gaslight papers closely resemble bromide in the points I hare already mentioned, so that it is not necessary to deal with them at length. I should like, however, to say that besides the "contrasty" qualities which are most used, are special kinds which, though very slow in action, walls give splendid results from dense negatives. These papers require a very strong light for printing, several fifty-candle-power lamps being needed in the printing boxes.
           Gelatino-chloride or P.O.P. was not o long ago almost universally used for portrait work, but is now little in favour, especially among the cheaper class of studios. A few good class firms still find that the warm tones so easily obtained upon it are acceptable to their patrons, and wisely adhere to it. Certain warm browns and reddish tints closely approach the delicacy of carbon, and will always be popular, but the purple black tones are now quite out of fashion, P.O.P. requires much greater cart- and cleanliness in working than bromide, which may account for the latter superseding it.
           Self-toning papers, which are mostly collodio-chloride, possess many advantages, although they are the slowest of the printing out sort. This defect may be largely overcome by employing an enclosed arc for printing, when the time in much shortened. A great range of tones from warm sepia to a blue-grey may be obtained by variation of the strength of the hypo bath and for the grays a preliminary soaking in a solution of common salt. Matt and glossy surfaces and white and cream bases are available in this class of papers. A variation of tone may be obtained by using a platinum toning bath as employed in the doable toning of ordinary collodio-chloride paper. I hare used much of this paper, and find that the prints stand very well. Some, which are fifteen or sixteen years old, seem quite fresh. Self-toning gelatino-chloride is also made, but I have not found so good a range of colours with them as with the collodion. Moreover, they cannot be dried by heat, as the latter can. Some few photographers have used what is termed salted paper for large work. This has to be prepared at home by coating drawing paper with a solution of chloride of ammonium or even common salt, and floating upon a bath of nitrate of silver. The prints may be fixed without toning, or they may be toned in any of the gold baths used for P.O.P. Strong negatives are required, as the image is inclined to be rather dull as compared with that on an emulsion paper. The surface is very agreeable, and with suitable subjects the results are highly artistic. Platinum printing like carbon stands in a category of its own, and occupies the first place with those photographers who put quality before cost. It is, next to ferro-prussiate, the simplest of all printing processes, and is not only pleasing but permanent; it is actually a "thing of beauty and a joy for ever." Platinum papers can be obtained in rough and smooth surfaces, end on white and cream bases. As there is no practically useful method of toning, special papers and solutions are prepared for black and sepia prints respectively. One important quality of platinum prints is their absolute flatness when finished; as there is no coating either of gelatine or collodion there is no risk of curling, and if attached by one edge to a mount they will lie close to it no matter what the condition of the atmosphere may be. It should be clearly understood that the word "platino," when applied to bromide paper, refers to nothing but the appearance of the surface. There is no platinum in the coating, and the image is no more permanent than that on ordinary bromide papers. Carbon printing is unique as regards the great variety of colour and surface in which prints may be produced. Although in portraiture only two or three are commonly used, such as sepia, red chalk, and warm black, at least fifty varieties of colour, including reds, blues, greens, browns, grays, and many others, and a score of different weights and surfaces in the transfer papers are regularly supplied. So that it is possible to make carbon prints which closely resemble those by any other photographic process; and, needless to say, all are absolutely permanent. It is worth noting that, in spite of war restrictions, the price of carbon materials has shown but little increase in price. Many are deterred from attempting carbon printing by the idea that it is very difficult, but this is not the case if ready sensitized tissue be used, and if the work be carried out systematically it is little more troublesome than P.O.P., and the extra price obtainable will amply justify the additional work.
           I have carefully abstained from giving working details of any process, us this has been done over and over again, out in case of any difficulty, any desired information will be given through the usual "Answers to Correspondents" column. My object has been to point out what materials photographers have to hand for the production of such prints as may be needed for any claw of business.

PRACTICUS.

Rabu, 14 Mei 2008

EX CATHEDRA

Over-printed self-toning paper.

           With some of the more recent batches of self-toning paper we have noticed a lack of uniformity. One batch that we were using lost very considerably in the fixing-bath, with the result that printing had to be carried much deeper in order to ensure the finished print being of the requisite depth and of a good colour. A later batch, upon fixing the first print or two, showed that it was one in which the prints lost very little, and we at first thought that owing to this difference the whole of the untoned and fixed prints (a very large number) were spoiled through the printing being carried too deeply. They were, however, saved in the following way. A bath containing 4 ozs. common salt in 10 of water was made up and the prints previous to fixing were placed in this for about fifteen minutes. Upon transferring to the ordinary fixing-bath they lost a good deal of depth, being reduced to just the right quality. The tone, of course, was modified, being of a cold black, and equal in every way to platinum-toned P.O. P. In fact, it is so satisfactory that many may decide to finish all their self-toning prints in this way instead of in the ordinary sepia that is so common. We wonder that more users of self-toning paper, and especially the collodion emulsions, do not favour this method more, as it yields prints of delightful richness and quality.

Describing second–hand goods.

           Those who have at any time had occasion to study the second-hand market must have found that many advertisers, both dealers and private individuals, frequently leave much to be desired in describing the goods that are for disposal. Take the case of apparatus with which the general photographer is not very familiar or that of an older pattern not to be found listed in any of the catalogues issued within the last ten years. We recently saw advertised, "A fine half-plate camera by - (naming a maker of a score of years ago), with two slides, no lens." This kind of advertisement, it must be admitted, gives little or no information as to the instrument for disposal, whether it is of single, double, or triple extension, whether it has a turn or tilting table, or a rising front or swing back, details that any practical worker purchasing a camera requires to have for his consideration. An older photographer might know that particular pattern even from the inadequate description giveu, but a modem worker certainly would not unless he happened to have catalogues hand of a score of years back. We have even seen lenses listed by first-class firms with a reputation for second-hand goods from which the aperture, focal length, and other important details were omitted. Advertisers of second-hand photographic apparatus will do well to put themselves in the position of the buyer when drafting out details of their goods, giving just those full details that they themselves would wish to have: a few words should not be omitted if their inclusion would give fulness to the description. It may be that an advertisement giving full information will be seen by a buyer on the look-out for the particular model of the" apparatus described, whereas he would not take the trouble to write to the vendor, if the goods were not fully detailed, for fuller particulars.

Rubber Stamps.

           As a rule a rubber stamp impression upon a mount gives an idea of cheapness, and quite spoils the effect of what might otherwise be an excellent production. This, like many other things, is due to a want of knowledge of the capabilities of our materials. To many people a rubber stamp is oval or circular in. form, the type plain black, and the colour of ink violet, and as far as ordinary office work is concerned these conditions are doubtless satisfactory. It is, however, quite possible to employ rubber stamps in such a way that they may be impressed upon the highest class of mount without being distinguished from lithographic or typographic work. In an instance which recently came under our notice a photographer used a steel die of his signature and town for stamping his mounts or prints. From this he had electros made which were used for printing upon mounts in brown ink. Finding the need for occasionally marking odd mounts and enlargements he sent the original die to a rubber stamp maker and received a rubber facsimile with box, pad and brown ink complete. With this outfit it was possible to sign mounts without causing anything unusual in their appearance. We have also seen the well-known square label form of address, "A portrait from the studio of - ," reproduced in the same way, the result being quite satisfactory. The secret of getting good impressions is to keep the pad and stamp free from dust. An old toothbrush is excellent for keeping the stamp clean, while the pad should be scraped the right way of the material with a blunt knife. When fresh ink is applied it should be well rubbed into the pad and allowed to remain for an hour or so before using. When long narrow stamps have to be used it is a good plan to have a small brass prong projecting from one side of the plate, so as to form two little feet, on which the stamp will stand squarely. These feet also afford a good means of keeping the lettering in correct alignment with the edge of the print.